We estimate the effects of health information technology designed to improve access to medication while limiting overuse through easier prescription renewal and improved information provision. We focus on benzodiazepines, a commonly prescribed class of mental health and insomnia medications, which are highly effective but potentially addictive. We study the staggered rollout of a nationwide electronic prescribing system over four years in Finland and use population-wide, individual-level administrative data sets. We find that e-prescribing increases average benzodiazepine use due to increased prescription renewals. The increase is most pronounced for younger patients. E-prescribing can improve the health of elderly patients and may help to balance the access-overuse trade-off. Without additional monitoring for addiction in place, it may, however, also have unintended health consequences for younger patients, who are more likely to develop mental and behavioral health disorders.